Bullshit.Well... depends. Some people especially moms want to take every possible item the child may need at all times. And that, combined with how massive a stroller + child seat is nowadays, may call for a larger boot.
OTOH I know someone who needed an A6 Avant to do this... which is a bit much
I had a kid and the stroller took up all the space in trunk of my Palio (a small-ish hatchback). Did I need a bigger car? Fuck no.
This annoys me SO MUCH. "I got a kid. Now I need a 3-row SUV for all the baby stuff!"
This is how we get the fuckton of CUVs SUVs WTUVs. Congrats. You killed the sedan.
/rant